The last few years have seen many advances in the calculation of multi-loop integrals and amplitudes 
[1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}, [18]}, [19]}, [20]}, [21]}, [22]}, [23]}, [24]}, [25]}, [26]}, [27]}, [28]}, [29]}, [30]}.
Two-loop 5-point amplitudes are at the frontier of current amplitude calculations and have been the subject of particularly intense research 
[31]}, [32]}, [33]}, [34]}, [35]}, [36]}, [37]}, [38]}, [39]}, [40]}, [41]}, [42]}, [43]}, [44]}, [45]}, [46]}.
That research has notably led to the calculation of the 2-loop QCD leading-colour amplitude for \(q\bar{q} \rightarrow {\gamma \gamma \gamma }\)  [42]}, [43]}, [44]}, which in turn has enabled, for the first time, the computation of the Next-to-Next-to-Leading-Order (NNLO) QCD corrections for a \(2\rightarrow 3\)  process [42]}, [51]}.
